OTTAWA — Canada’s largest police forces are grappling with how to reliably — and quickly — get blood samples from suspected drug-impaired drivers in order to use new criminal charges created ahead of the legalization of recreational marijuana.

Under the new law, police can demand a blood sample once they have reasonable grounds to believe a person is impaired, such as a failed field sobriety test or a positive result on a saliva-testing device.

In big cities, police forces are likely to sign contracts with medical specialists who would be on call 24 hours a day to come to police stations and draw blood within the legally required two-hour window after the suspect has been driving.

But it’s not yet clear how police in smaller cities and rural areas will solve the logistical problem of getting a blood sample from a driver within two hours. It’s possible that police officers in some regions could eventually be trained to draw blood themselves, though no police force has yet confirmed that is their plan.

The Calgary Police Service is one of the forces that’s farthest along in dealing with this issue, and hopes to have a contractor in place soon for drawing blood.

“This is admittedly a new area that we have not pursued before in policing,” said Sgt. Richard Butler, who heads the Calgary police’s impaired driving unit. “Any time we’ve pursued taking blood from impaired drivers, it’s always been in a hospital setting.”

A drug-impaired driver can still be prosecuted without a blood sample, through the use of a urine sample and examination by a drug-recognition expert. But such cases take about twice as long to prosecute as alcohol-impairment cases, and have a lower conviction rate (about 60 per cent nationally, according to Statistics Canada, compared to 80 per cent for alcohol).

Bill C-46 created a new class of offences based on blood drug concentration, which allows for much easier prosecution. If lab results show a driver’s THC in the blood is above a certain level, police can criminally charge the driver without having to further prove impairment.

But to hold up in court, the blood sample must be taken within two hours of driving. To facilitate that, Bill C-46 removed the requirement that a doctor must supervise the drawing of blood. Now the blood sample can be taken by a qualified blood technician, a designation set by a province’s attorney general.

The drawing of blood must be done very carefully — not only for health reasons, but also because defence lawyers will challenge any scenario where the sample may have been mishandled.

In cases involving a collision, a driver is frequently taken to hospital anyway, making it easy to get an expert to draw blood. It is the other cases, such as drivers arrested at a checkstop, where the blood sample issue needs solving.

It’s not yet clear how police in smaller cities and rural areas will solve the logistical problem of getting a blood sample from a driver within two hours.Mike Hensen/Postmedia/File

Butler said the Calgary Police are negotiating a contract that would see qualified technicians on call around the clock to come to a police station within 20 minutes and draw a blood sample from someone arrested for impaired driving.

He declined to get into details, but Butler acknowledged it was going to be very expensive — especially because they’ll need more than one technician on call. “If they have to respond within 20 minutes, it can take an hour just to get from one side of the city to another,” he said.

Most other large police forces told the National Post they have not yet settled on a plan for drawing blood. The Winnipeg Police Service said there is a “process that we have established for situations where the suspect is not already being taken to hospital,” but did not provide details.

It is in rural areas where the situation will be toughest, as officers are sometimes patrolling hours away from their station. “I know there has been some consideration for some of the rural, or even some of the smaller towns, to actually train their own members in phlebotomy to take the blood,” Butler said, but added he didn’t know if that would be pursued.

“At this point the RCMP are not drawing blood,” said an RCMP official at an Oct. 5 briefing in Ottawa, which was conducted on the condition names not be used. He said he expects police forces will instead look to find medical contractors.

“There are active discussions going on right now to identify who that (blood technician) is, recognizing every situation will be different,” the official said.

Once police forces are set up to take blood samples, the next challenge will be processing them efficiently. The head of the RCMP’s national forensic labs, which serve police forces outside of Ontario and Quebec, warned senators studying the bill that the labs are already “operating at or close to full capacity,” and won’t be fully set up to handle the increased drug toxicology workload until 2021.